Steel joist connection



July 16, 1968 l. J. M M U 3,392,499

STEEL JOIST CONNECTION Filed May 2. 1966 3 Sheets-Sheet l INVENTOR. IRA J. M: MANUS I. J. M MANUS July 16, 1968 STEEL JOIST CONNECTION 5 Sheets-Sheet t'I Filed May 2, 1966 1 N VEN TOR. IRA J. MCMANUS July 16, 1968 J. MCMANUS 3,392,499

STEEL JOIST CONNECTION r lle y 4. 1966 5 Sheets-Sheet 5 INVENTOR. IRA J. McMANUS United States Patent 3,392,499 STEEL JOIST CONNECTION Ira J. McManus, 39 Lincoln Ave.,

Florham Park, NJ. 07932 Filed May 2, 1966, Ser. No. 546,648 Claims. (Cl. 52-483) ABSTRACT OF THE DISCLOSURE A steel joist end connection for a building structure to provide an improved joist keying end construction when said joist is welded to a supporting girder and subsequently encased by a concrete slab.

My invention relates generally to steel joists used in the construction of steel and concrete buildings and is directed particularly to improvements in end connections of standard open-web steel joists where they join supporting steel beams.

Open-web steel joists are commonly fabricated of a pair of angle-iron flanges welded in opposed relation along the apices at one side of a zi-g-zag bar web, to form a top chord, and a pair of longitudinal bars or the like welded along the apices at the other side of the bar web to form the bottom chord. Such joists are generally welded between steel framework beams or girders to provide the supporting structure for concrete slab floors and the like. In ordinary construction, the top chords of the steel joists are joined to the top flange of framework girders or beams by horizontal extension bars, flanges or the like welded between end portions of the joist web somewhat below the upper chord, and the top flanges of the associated girder or beam. The concrete slab is poured upon forms placed on top of the joists, whereby the bottom of the slab is supported in vertically spaced relation above the top of the supporting beam or girder.

It is accordingly one of the principal objects of this invention to provide an improved joist end construction that, when welded to the supporting girder or beam top flange and subsequently encased by the concrete slab, allows the concrete slab and the supporting girder or beam to act together in composite action, resulting in economics due to savings in weight of the supporting girder or beam.

It is another object to provide an improved end connection for open-web steel joists wherein the top chord of the joists will be substantially at the level of the top flange of the supporting girders or beams, thereby readily permitting marginal portions of a concrete floor to be placed in bearing relation upon top portions of supporting girders or beams. With such construction, the concrete floor slab is in rigid connection with supporting girder or beam steel to act in unison therewith and increasing the rigidity of the floor or roof system.

Another object is to provide an end connection for open-web steel joists that can readily be pro-fabricated in the shop, for the most part, requiring only a few easilyperformed welding operations on the job, thereby effecting composite action with further economies in time and labor.

Another object is to provide an end connection of the character described a major portion of which will extend up into a-concrete slab or floor it supports so as to be encased therein.

Yet another object is to provide an end connection of the character described that raises the supporting steel relative to the top of the concrete floor in steel framework building construction, thereby permitting a reduction in floor-tofloor heights for given ceiling heights.

A more particular object is to provide an end connection for open-web steel joists comprisinga vertical shear plate welded to and extending outwardly and upwardly of the end portion of a top chord of a steel joist, and a horizontally-extending bed plate welded or otherwise secured against the underside of the shear plate at the outwardly-extending end thereof and adapted to seat upon the top flange or other surface of a supporting framework girder.

Yet another object is to provide an end connection of the character described and further including a short, horizontally-extending bar secured to the outer end of the shear plate near the upper end thereof to enhance the locking action of a concrete floor slab or the like poured over said end connection.

Other objects, features and advantages of the invention will be apparent from the following description when read with reference to the accompanying drawings. In the drawings, wherein like reference numerals denote corresponding parts throughout the several views:

FIG. 1 is an oblique view, as seen from the top of a steel joist end connection embodying the invention shown connected to a support girder, partially shown;

FIG. 2 is a side elevational view of the end connection illustrated in FIG. 1, illustrating the use of form plates therewith for forming a concrete floor slab over a series of steel joists;

FIG. 3 is a modified form of the invention illustrating, in oblique view as seen from the top, an end connection for use with steel joists having single top and bottom chords formed of sheet steel bent into channel shape;

FIG. 4 is a side elevational view of the end connection illustrated in FIG. 3, illustrating the use of form plates therewith for forming a concrete floor slab over a series of joists;

FIG. 5 is a side elevational view of a modified form of the end connection illustrated in FIGS. 1 and 2;

FIG. 6 is a vertical cross-sectional view taken along the line 66 of FIG. 5 in the direction of the arrows;

FIG. 7 is a side elevational view of another modified form of the end connection illustrated in FIGS. 1 and 2.

Referring now in detail to the drawings and considering first the embodiment of the invention illustrated in FIGS. 1 and 2, l0 designates a typical open-web steel joist comprised of a pair of angle irons 11, 12 Welded opposedly along the apices at one side of a zig-zag bar web 13, to form the top chord of the joist, and a pair of steel rods 14, 15 welded opposedly along the apices at the other side of the bar web 13 to form the bottom chord of the joist. The end connection embodying the invention comprises an elongated steel vertical shear plate 16, about 10 inches long for example, one end of which is welded edgewise to the top of the joist top chord angle irons 11, 12 so that the other end of said shear plate extends outwardly of the joist to an extent of about one-half its length. Preferably, the thickness of the shear plate 16 is such as to just fit between the opposed surfaces of the top chord angle irons 11, 12 to facilitate welding thereat as is best illustrated at 17 in FIG. 1. Welded against the lower edge of the shear plate 16, as indicated at 18, is a rectangular steel bearing plate 19. The upper corner at the outer end of the shear plate 16 is notched to receive a short, transversely-extending bar 20, welded in place therein as indicated at 21. The bar 20 serves as additional means for keying the end connection in a concrete slab as is hereinbelow more fully described.

It is to be understood that the above-described end connection for the joist 10 is preferably fabricated in the shop so that the assembly need merely be set in place between The usual sheet metal form plates 24 placed upon the erected joist form the bottom of the' concrete slab 25 (see FIG. 2). In use of the end connection, the form plates 24 are placed to extend over the top of the supporting girder, as illustrated in FIG. 2, so that the slab 25, when poured, will have marginal portions bearing upon the supporting structure, and so that the concrete slab will at the same time encase the end connections.

FIGS. 3 and 4 illustrate a modified form of the invention wherein the top chord 10a and bottom chord 14a are each comprised U-shaped channel members integrally formed with opposed, outwardly-extending flange portions 26, 27 and 28, 29 respectively. The top and bottom chords 10a, 14a are arranged with their flange portions 26, 27 and 28, 29 at the outside, or top and bottom, respectively, and the end portions of the bottom chord 14a are bent upwardly as indicated at 30 in FIGS. 3 and 4 to join the top chord 10a at the ends of the joists, whereat they are welded. The shear plate 16a has a downwardly-extending rear portion 16 which fits within the channel recess 31 in the top chord 10a, whereat it is welded as indicated at 32. The construction and operation of the end connection illustrated in FIGS. 3 and 4 is otherwise the same as that of FIGS. 1 and 2 described above.

FIGS. and 6 illustrate another modified form of the invention wherein the two angles comprising the top chord is reinforced by two additional angles which are arranged and welded together in upper and lower spaced pairs 33, 34 and 35, 36 respectively, the side flanges of which extend outwardly from the tops and bottoms of said angle-iron pairs respectively. The upper apices of the zig-zag bar web 13 extend upwardly midway between the composite top chord, whereat they are welded in place. The shear plate 16c diiTers from the shear plate 16 of the embodiment illustrated in FIGS. 1 and 2 only in that it hasa downwardly-extending rear portion 16d which fits down between the upper spaced pair of angle irons 33, 34 at the end of the joist, whereat it is welded in place. The construction and operation of the end connection illustrated in FIGS. 5 and 6 is otherwise the same as that of FIGS. 1 and 2.

FIG. 7 illustrates still another embodiment of the invention intended for heavier loadings which differs from the embodiment illustrated in FIGS. 1 and 2 only in that the shear plate 16e is formed with a downwardly-extending rear portion 16 which projects below the top chord angle irons 11, 12. In addition, the upwardly-extending end portion 37 of the web bar 13 terminates between the angle irons 11, 12 just behind the shear plate 16e whereat it is welded as indicated at 38; and the ends 14a, 15a of the bottom chord rods 14, 15 are bent upwardly to terminate in abutment with the opposed sides of the downwardly-projecting' portion of the shear plate 162, against which they are welded as indicated at 39. The construction and operation of the end connection illustrated in FIG. 7 is otherwise the same as that of FIGS. 1 and 2. Referring again to FIGS. 1 and 2, it is contemplated that the shear plate 16 could be cross-drilled in three or more positions as indicated at 40 to provide keyways for enhancing the keying action of the concrete floor slab t0 the end connection. v While I have illustrated and described herein only four forms in which my invention can conveniently be embodied in practice, it is to be understood that these forms are presented by way of example only and not in a limiting sense. The invention, in brief, includes all the 4 forms and embodiments coming within the scope and spirit of the following claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a steel joist end connection for steel joists of the type having an elongated top chord and a bottom chord fixed in spaced relation below and along said top chord, the combination comprising a vertical shear plate welded to and extending outwardly and upwardly above the end portion of the steel joist top chord, a horizontally-extending bed plate secured against the underside of the shear plate at the outwardly-extending end thereof, and a transversely extending bar keying means at the top of the vertical shear plate, and form plate means lying below the top surface of said shear plate, whereby a concrete slab portion encasing said shear plate engages the form plate means and said keying means.

2. steel joist end connection as defined in claim 1' wherein said keying means comprises a steel bar fixed to said shear plate and extending outwardly of each side thereof.

3. A steel joist end connection as defined in claim 1 wherein said top chord of said steel joist comprises a pair of elongated U-shaped channel members secured in upper and lower back-to-back relation, each channel member having integrally formed at its outer ends outwardly-extending opposed flange portions, said shear plate having a downwardly-extending portion seated and secured within the recess defined at the end of the upper of said U-shaped channel members.

4. A steel joist end connection as defined in claim 1 wherein said top chord of said steel joist comprises a pair of elongated angle iron members arranged in spaced parallel relation, said shear plate having a downwardlyextending portion fixed between the end portions of said angle iron members, said downwardly-extending portion projecting below said angle iron members, said bottom chord being comprised of a pair of steel rods secured in spaced parallel relation, outer end portions of said steel rod being bent upwardly to terminate at one side of each 'of'said projecting portion of said shear plate and being welded thereat.

5. A steel joist end connection as defined in claim 4 including a zig-zag bar extending along and between said top and bottom chords, the apices along the top of said zig-zag bar being welded between said angle iron mem bers, and the apices along the bottom of said zig-Zag bar being welded between said steel rods.

References Cited UNITED STATES PATENTS 1,662,752 3/1928 Lucy 52-691 1,915,424 6/1933 Ken 52-691 1,936,147 11/1933 Young .L.. 52-334 1,952,235 3/1934 Cameron 52-691 1,969,312 8/1934 Macomber 52-692 1,979,643 11/1934 Sahlberg 52-334 2,055,701 9/1936 Palmer 52-334 2,256,812 9/ 1941 Miller 52-691 FOREIGN PATENTS 1,335,345 2/ 1964 France.

MARION PARSONS, 111., Primary Examiner.

CARL W. TOMLIN, Examiner. 

